It feels counterintuitive. You have hundreds of products. Your customer just landed on your store. Shouldn't you show them as much as possible to maximize the chance something catches their eye?

The research says no. And if you run personalized discount campaigns, understanding why is the difference between a campaign that converts and one that overwhelms.

The paradox of choice

Psychologist Barry Schwartz popularized the concept in his landmark book: when people face too many options, they don't choose more confidently. They freeze. They second-guess. They leave.

The classic study by Sheena Iyengar at Columbia demonstrated this with jam tastings. A display of 24 jams attracted more browsers, but a display of just 6 jams converted 10 times more buyers. People looked at the big display, felt overwhelmed, and walked away empty-handed.

The same principle applies to your discount catalog. When a customer opens an email or sees a theme block with 20 discounted products, the mental load spikes. Which one is the best deal? Am I missing something better if I scroll down? Should I compare all of these before deciding?

Decision fatigue doesn't make customers choose the wrong product. It makes them choose no product at all.

The sweet spot: 4 to 6 products

Across merchants using personalized catalogs, a common pattern emerges: catalogs with 4 to 6 products tend to do well on click-through, add-to-cart, and conversion rate. Think of it as a recommended starting point, not a rule — the right number depends on your store, your products, and how much catalog the plan you are on supports.

Here is why that range tends to work:

  • Scannable at a glance. Four to six products fit on one screen. The customer sees the full offer without scrolling, which means they engage with it immediately instead of treating it like a browsing session.
  • Each product carries weight. When there are only five items, each one feels hand-picked. The customer perceives curation, not a clearance bin.
  • Faster decisions. Comparing five options takes seconds. Comparing twenty takes minutes — minutes most customers won't spend.

Fewer products does not mean less variety

This is the key insight merchants miss when they first hear "use smaller catalogs." They worry that limiting each catalog to 6 products means their full product range never gets exposure.

With randomized personalized catalogs, the opposite is true. If you have 200 products in your strategy's collection and each customer sees 6, that's potentially dozens of unique catalog combinations going out in a single campaign. Your entire catalog gets exposure — it's just distributed across customers instead of dumped on each individual.

Randio tip: The collection strategy has a "max products" setting — 6 is a good starting point. Every customer then receives up to 6 products drawn randomly from your collection, each at a unique discount within your defined range. Your full collection still participates — each customer just sees a curated slice of it.

When to test larger catalogs

There are cases where slightly larger catalogs make sense:

  • Low campaign frequency. Catalog size and how often you send pull in opposite directions. If you send often, keep each catalog small and quick to act on — a frequent offer should feel light. If you send rarely, a fuller catalog (up toward the 12 max) earns its place: the offer is an event, so customers will spend more time with it.
  • Broad product categories. If your store sells across very different categories (e.g., home decor, kitchenware, and apparel), a customer might need 8-10 products to see at least one or two from categories they care about.
  • High AOV stores. Customers buying expensive items often want to compare more options before committing. Eight products can work well here.
  • Re-engagement campaigns. Returning customers who already know your brand may tolerate larger catalogs because they process the options faster.

The current maximum is 12 products per catalog. Even when a larger catalog fits your store, climb toward that ceiling deliberately — the cognitive overhead rises as you add more, so add products because a test shows they help, not by default.

How to measure it

The simplest test: run one campaign with a smaller catalog (say 6 products) and another with a larger one (up to the 12 max) on a similar customer group, then compare conversion rate directly. Let your own numbers settle it rather than any rule of thumb.

Many merchants find the smaller catalog converts better — the larger one may draw more browsing, but browsing without buying is just cost. That said, it genuinely varies by store, so trust your test.

The randomization handles variety across your customer base. Your job is to find the catalog size that makes the individual experience feel focused — for your products and your customers.

If you're setting up your first campaign, 4-6 products is a sensible place to start. Adjust from there based on what your results — and your plan — support.